In most rice cookers on the market, the temperature-controlled components are consisted of caps and NTC thermistors. The upper surface of the cap is in contact with the inside of rice cooker; NTC thermistor is covered with heat-shrinkable tube and Teflon tube, then be folded into a U shape; The NTC thermistor, i.e. the bottom of the U shape, is pressed on the back of the upper surface of the cap to achieve temperature control of the rice cooker.
This assembly process and structure will result in a gap between the thermistor and the back of the upper surface of the cap, make a difference in the thermal coefficient of the heat-shrinkable tube and Teflon tube which is covered on thermistor; And the heat conductivity of the cap is good, while the heat dissipation is also large, so that the heat is not fully transmitted to the thermistor. These reasons lead to the temperature measurement results of the inside of rice cooker with hysteresis quality, high error, and the hysteresis quality is uncertain, can’t be overcome by pre-fabricated advance; The NTC thermistor, its structure is mechanical riveting type, less adaptable to vibration, high-temperature environment, there may appear riveting end loose, low reliability.
In order to overcome the shortcomings of existing technology, let’s introduce a temperature-controlled component of rice cooker which can measure the temperature of inside of rice cooker quickly, accurately, reliably. This temperature-controlled component include cap, housing, NTC thermistor, wires, and connectors. Its housing consists of a thermocouple grid, tube, tube connected on the back of the thermocouple grid; The upper surface of the cap has through hole, thermistor is installed in the through hole of the cap, the front of thermocouple grid is flush or slightly above the upper surface of cap; NTC thermistor is fixed in the tube, then is led to connect to the connector by wire.
There is a hole at the joint of tube, and the depth of hole is not less than 0.1mm. NTC thermistors can get closer to the inside of rice cooker, reducing the hysteresis quality of temperature measurement. Thermistor is R-type glass sealed NTC thermistor, with characteristics of vibration resistance, high temperature resistance, high sensitivity of temperature, strong environmental adaptability, which is the core part of the temperature sense and temperature measurement of temperature-controlled component. After the thermistor is installed, which is encapsulated in tube with epoxy resin, silicone or ceramic gel, on one hand, it play a role of fixing NTC thermistor to ensure its pressure-resistant insulating property; On the other hand, makes housing conduct heat on NTC thermistor, improve the sensitivity and accuracy of the measurement. Cap and housing can be made of aluminum, copper, stainless steel or other metals and high temperature-resistant plastics with better thermal conductivity.
NTC thermistor produced by EXSENSE Electronic Technology Co., Ltd. has characteristics of excellent reliability, high sensitivity and high precision, which can measure temperature and control temperature effectively and rapidly. It plays an indispensable role in smart home, medical equipment, electronic products and other fields.